6 core third party data companies as of 2017.
You can also work with partner agencies that have a dedicated reps to target via custom clusters.
The effectiveness of this data varies.
Many partners require higher minimum ad spends e.g. $50k/month or more for you to meet the requirements.
ADVANCED ONBOARDING Examples
Target new & current customers on Facebook
Leverage existing customer databases to find your best customers on Facebook,
and then find more people who are just like them.